THE impact of anesthesia on the developing brain continues to be hotly debated. In this issue, Hu et al.,1 from the Mayo Clinic, Rochester, Minnesota, report an association between childhood exposure to multiple anesthetics and increased risk of learning disability and attention-deficit/hyperactivity disorder (ADHD). The study uses a well-established birth cohort and is similar to two studies published previously by the same Mayo Clinic group.2,3 The earlier studies were criticized for including children who were anesthetized in an era that relied on somewhat outdated drugs and monitoring. The study reported in this issue included children anesthetized with more contemporary agents and monitoring. The results are almost identical to the previous studies. All find an association between exposure to anesthesia in early childhood and subsequent diagnosis of learning disability and/or ADHD, and the associations were stronger with multiple exposures compared with single exposures.